Simplified metering pump

ABSTRACT

A metering pump including a main body having a first surface, a member for attachment to a bottle, an inlet valve, an elastomeric head having a second surface, where both surfaces define a pumping chamber, and a discharge valve having a valve seat and a moving member adapted to move between a first closed position and a second open position. The moving member extends from the head forming a partition and is integral with the head. The first and second surfaces are relatively movable therebetween causing pumping of a liquid. When the moving member is in the first position and there is a reduced pressure in the pumping chamber, the reduced pressure then presses the moving member against the valve seat.

DESCRIPTION

1. Field of the Invention

The invention relates to a simplified metering pump, particularly a pumpcomprising: (a) a main body having a first surface, (b) first means forattachment to a bottle neck, (c) second means for attachment of a diptube, (d) an inlet valve, (e) a head, where the head has a secondsurface facing the first surface, and where the first surface and thesecond surface define a pumping chamber, where the head is made from amaterial having elastomeric properties adapted to be resilientlydeformed by a manually applied force and has an external actuationsurface adapted to be deformed by a user's finger, and (f) a dischargevalve at the outlet of the pumping chamber, where the discharge valvecomprises a valve seat and a moving member adapted to move between afirst position, corresponding to the closed discharge valve and in whichthe moving member contacts the valve seat, and a second position,corresponding to the open discharge valve, where the moving memberextends from the head forming a partition, where the moving member isintegral with the head, and where the first surface and the secondsurface are adapted to perform a relative movement therebetween causingthe pumping of a liquid between the inlet valve and the discharge valve.

In the present description and claims, it is to be understood that amaterial having elastomeric properties is any material capable of beingsubjected to a resilient deformation sufficient to fulfill therequirements of the invention, particularly, capable of generating apumping effect of a liquid contained in a bottle. Thus, not only mustthe conventional elastomeric materials be included in this group ofmaterials, but other plastics materials must also be included, such asfor example polypropylene, that, with an appropriate geometry, may besubjected to considerable resilient deformation and may recover theirinitial shape when the external force causing their deformation ceases.

2. State of the Art

Various embodiments of metering pumps are known for a plurality ofapplications. Metering pumps are frequently attached to disposableliquid containers. In this sense, the cost of the pump has to be verylow, since it must not appreciably affect the product total cost. On theother hand, apart from performing the technical function of pumping theliquid, the metering pump frequently has to have a particular aestheticappearance, a fact that often imposes serious geometrical limitations,which have to be compatible with the correct working of the pump. Inthis sense, there is a permanent need for developing new simplifiedmetering pumps, allowing for cost savings and limiting as little aspossible the aesthetic appearance it is wanted to confer on the pump.

In U.S. Pat. No. 3,820,689, published on Jun. 28, 1974, there isdescribed a metering pump of the type mentioned above. Nevertheless,this pump has a number of drawbacks, particularly, it is hard to obtaina good pumping effect with it.

SUMMARY OF THE INVENTION

The invention aims to overcome these drawbacks. This aim is achievedwith a simplified metering pump of the type first mentioned abovewherein when the moving member is in the first position, and there is areduced pressure in the pumping chamber, the reduced pressure thenexerts a force pressing the moving member against the valve seat.

In fact, in this way it is possible to improve the pumping effect. Inthe pump described in U.S. Pat. No. 3,820,689 mentioned above, thedischarge valve does not close optimally, because when there is areduced pressure in the pumping chamber, thanks to which it is filledwith liquid from the reservoir, the discharge valve is then closed dueonly to the resilient forces of the head, which is made from a materialhaving elastomeric properties. Nevertheless, the reduced pressure in thepumping chamber tends to open the discharge valve, because the dischargevalve has downstream the atmospheric pressure of the externalenvironment, whereby the pressure differential acts against closing ofthe discharge valve. Nevertheless, in the pump according to theinvention, the moving member is disposed such that the reduced pressurein the pumping chamber forces the moving member against the valve seat.In this way, the reduced pressure in the pumping chamber helps theresilient force of the elastomeric head to keep the discharge valveclosed, namely, the resilient recovery force and the force due to thereduced pressure in the pumping chamber act in the same direction. Inother words, the moving member of the discharge valve has two faces, oneof them oriented upstream (the inner face) and the other one orienteddownstream (the outer face). Thus, when the discharge valve is closed,the moving member has the face oriented upstream (the inner face)subject to the reduced pressure inside the pumping chamber, while theface oriented downstream (the outer face) is subject to the atmosphericpressure of the external environment. Therefore, the pressuredifferential tends to move the moving member in the upstream direction,pressing it against the valve seat. This improves the closing of thedischarge valve, which prevents air from entering the pumping chamberand improves the pumping effect of the pump.

Generally, the partition forming the moving member may have anygeometry, either flat, in the form of a cylindrical surface, in the formof a spherical cap, undulated, etc. The only requirement is that theforce caused by the pressure difference (reduced pressure in the pumpingchamber and atmospheric pressure at the outlet of the discharge valve)should press the partition against the valve seat, which consistsbasically of a frame against which the perimeter of the partition willbear. Nevertheless, the partition is preferably a flat surface or acylindrical surface. Specifically, the cylindrical surface allows it tobe housed better in the ensemble of the pump, in which the majority ofthe surfaces in its surroundings are also cylindrical.

A preferred embodiment of the invention is obtained when the partitionis a cylindrical surface extending over a certain relatively smallangle, generally less than 90° and even less than 45°. Thus, the curvedshape of the partition does not make it excessively rigid so that it canmove by flexure. Nevertheless another preferred form of the invention isobtained when the partition is a cylindrical surface extending over360°, i.e. such as to form a cylinder surrounding the second surface. Inthis case, the discharge valve communicates the pumping chamber with anannular discharge conduit surrounding the entire pumping chamber. Inthis case the valve seat is preferably formed by a second alsocylindrical partition and is disposed in the main body such that thesecond partition surrounds the first surface. Thus, the partition (whichis the moving member of the discharge valve) bears against the secondpartition (which is the frame or fixed member of the discharge valve)when the discharge valve is closed. When the liquid contained in thepumping chamber is compressed, the cylindrical partition bends totallyoutwardly allowing the liquid to flow to the annular discharge conduit.

The second surface is advantageously convexly curved towards theexterior of the pumping chamber and preferably is a spherical cap. Infact, this geometry optimizes the pumping chamber for a minimum surfaceof the head. Furthermore, it has a good resilient recovery force,causing the external actuation surface to return to its originalgeometry, overcoming the reduced pressure generated inside the pumpingchamber. Alternatively it is possible to make the second surface flat.In this case, the external actuating surface of the head does notproject above its surroundings, which allows for the design of pumps,which, for example, may be piled on the head.

The first surface is advantageously provided with a portion concavelycurved towards the interior of the pumping chamber, and it is preferablya spherical portion. As in the case commented above, this geometryoptimizes the volume of the pumping chamber with regard to the areathereof. But this geometry is particularly effectively adapted to theshape to be assumed by the second surface when deformed by a finger.

Furthermore, it is particularly advantageous for the curved portion andthe second surface to make contact in the limit of the stroke followedby the second surface during a pumping movement. In this way theresidual volume of the pumping chamber is minimized, whereby the size ofthe pump may be optimized. It is likewise particularly advantageous forthe curved portion to have an outer rim that is convex towards theinside of the pumping chamber. This outer rim serves as a support forthe second surface, allowing it to deform more “smoothly”, avoiding theformation of major deformations (and, therefore, major stresses) at theedge of the second surface, i.e. in the portion where the head memberwhich moves and the head member which is attached to the rest of thepump are connected. Furthermore, the outer rim serves to reduce evenmore the residual volume of the pumping chamber. Finally, it also servesto facilitate the recovery of the second surface to its originalposition (extended position).

The valve seat preferably has a rounded contact surface with the movingmember. This geometry improves the seal between the partition and thevalve seat, because when the partition is deformed by the pressuredifferential between the pumping chamber and the outside, thisdeformation causes the support surface between the partition and theframe to be increasingly greater, whereby the force tending to close thepartition is distributed over a larger area. For the same reason, themoving member advantageously has a contact portion with the valve seatthat is increasingly thinner towards its free end.

In the pump according to the invention the head has two members, theexternal actuation surface with its corresponding second surface and themoving member of the discharge valve defining a partition, which havetotally different functions. Nevertheless, the head is an integral unitand is made from an elastomeric material, whereby the deformationundergone by the head during pumping, which should strictly be locatedon the external actuation surface, may really extend to affecting themoving member of the discharge valve, influencing the closing thereof.It is therefore advantageous for the pump to have at least one column onthe first surface extending towards the second surface and disposed in aportion proximate the discharge valve. In fact, in this way the columnacts as a stop such that the deformation of the head is stopped by thecolumn and the head portion where the moving member of the dischargevalve is disposed is not affected. There are advantageously two columns,such that there is a broad passage between them for the pumped liquid.The columns preferably have such a height that they contact the secondsurface when the second surface is in its extended position. In thisway, immediately the deformation of the external actuation surfacestarts, the columns perform their support function and the portion ofthe head where the moving member of the discharge valve is located isnot deformed in any way due to the deformation of the external actuationsurface.

The pump according to the invention may have a main body which is asingle part comprising first attachment means to the neck of the bottle,second attachment means of a dip tube, and the seat of an inlet valve.This solution reduces the number of components of the pump to a minimum.

Another preferred embodiment of the invention is obtained when the pumphas, apart from a main body, an attachment body comprising the firstattachment means, where the attachment body is attached to the main bodywith the possibility of a relative displacement between an open positionand a closed position and wherein the attachment body comprises aprojection which, when the attachment body and the main body are in theclosed position, prevents the second surface from performing saidrelative movement. In fact, although this variant of the pump has onemore part than the previous one, in this way, it is possible to have asealing mechanism preventing discharge of liquid by inadvertent pumping,for example during the transportation and handling of the pump.

Preferably the projection is a tubular stem surrounding the inlet valve.The projection thus serves also to close the passage of the inlet valve,which also prevents liquid spillages caused by over-pressurizing thecontainer and/or placing it upside down. This is achieved preferably byhaving the projection hermetically sealed against the second surfacewhen the attachment body and the main body are in the closed position.

Advantageously, the relative displacement is greater than the relativemovement. There is thus ensured, on the one hand, that the projectionmakes contact with the second surface when it is in the closed positionand, on the other hand, that the second surface does not contact theprojection when the pump is in its open position but when the secondsurface is in the limit of deformation due to the pumping movement.There may thus be included lips on the second surface improving the sealwith the projection when the pump is in the closed position, withoutrunning the risk of these lips contacting the projection during apumping movement, since otherwise the risk would be run of the secondsurface becoming blocked with the projection and not being able toreturn to its initial position (extended position).

The main body preferably comprises a first annular lip acting as a sealwith the outer wall of the tubular stem.

The main body advantageously comprises a second annular lip acting as aseal with an annular partition disposed in the attachment body when thepump is in the closed position, where the annular partition surrounds aventilation hole. There are thus avoided possible liquid losses throughthe ventilation hole.

BRIEF DESCRIPTION OF THE DRAWINGS

Further advantages and features of the invention will become evidentfrom the following description in which preferred embodiments of theinvention are described without any limiting nature, with reference tothe accompanying drawings, in which:

FIG. 1 is longitudinal section view of a pump according to theinvention, in the open position.

FIG. 2 is a cross section view of the pump of FIG. 1 in the closedposition.

FIG. 3 is a longitudinal section view on the line III-III of theattachment body of the pump of FIG. 1.

FIG. 4 is an elevation view of the attachment body of FIG. 3.

FIG. 5 is a top plan view of the attachment body of FIG. 3.

FIG. 6 is a bottom plan view of the head of the pump of FIG. 1.

FIG. 7 is a longitudinal section view of the head of FIG. 6.

FIG. 8 is a bottom perspective view of the head of FIG. 6.

FIG. 9 is a longitudinal section view of the main body of the pump ofFIG. 1.

FIG. 10 is a front elevation view of the main body of FIG. 9.

FIG. 11 is a top plan view of the main body of FIG. 9.

FIG. 12 is a top perspective view of the main body of FIG. 9.

FIG. 13 is a top perspective view of the pump of FIG. 1 in the openposition.

FIG. 14 is a top perspective view of the pump of FIG. 2 in the closedposition.

FIG. 15 is a longitudinal section view of the pump of FIG. 1 with thesecond surface deformed.

FIG. 16 is a longitudinal section view of a second pump according to theinvention.

DETAILED DESCRIPTION OF EMBODIMENTS OF THE INVENTION

FIG. 1 shows a simplified metering pump according to the invention. Itcomprises a main body 1, a attachment body 3, a head 5 and a ball 7which is the moving member of a inlet valve 9 disposed in the attachmentbody 3. The main body 1 has a first surface 11 facing a second surface13 disposed in the head 5. Between these two there is defined a pumpingchamber 17. The head 5 is made from a material having elastomericproperties and has an external actuation surface 15 adapted to bedeformed by a user's finger between an extended position, correspondingto the rest position shown in FIG. 1, and a deformed position,corresponding to the end of pumping position shown in FIG. 15. Theexternal actuation surface 15 coincides substantially with the secondsurface 13, bearing in mind only that the external actuation surface 15is the one physically in contact with the outside and with the user'sfinger and the second surface 13 is the surface facing the inside of thepump, concretely towards the pumping chamber 17.

FIG. 1 also shows a dip tube 19 attached at one end to the attachmentbody 3 by second attachment means formed substantially by a cylindricalprojection adapted to house the dip tube 19 therein. The dip tube 19 hasthe other end thereof dipped in the liquid to be pumped contained in abottle, not shown in the drawing figures.

The attachment body 3 is provided with first attachment means consistingof a threaded portion 21 adapted to be attached to a bottle neck, it isalso provided with protrusions 23 housed in helical grooves 25 disposedin the main body 1 so that when the main body 1 is rotated relative tothe attachment body 3, apart from the rotary movement there is atranslation movement along the longitudinal axis of the pump, wherebythere is achieved a relative displacement between the attachment body 3and the main body 1 between an open position, as shown in FIG. 1, and aclosed position, as shown in FIG. 2. The attachment body 3 has,furthermore, a projection in the form of a tubular stem 27 thatsurrounds the inlet valve 9 and extends along the longitudinal axistowards the head 5.

When the pump is in the closed position the tubular stem 27 is insertedinside the pumping chamber 17 up to touching the head 5, precisely thesecond surface 13. The second surface 13 is provided with a secondcylindrical projection 29 that improves the seal between the secondsurface 13 and the tubular stem 27. Thus the inlet valve 9 is completelyclosed such that the liquid contained in the bottle cannot flow throughthe inlet valve 9 and be poured outside although the inside of thebottle is overpressurized and/or the bottle is placed upside down.

The main body 1 has a first annular lip 31 sealing against the outsidewall of the tubular stem 27. In this way, the pumping chamber 17 issealed without any possibility of the liquid held therein flowing insidethe main body 1.

The pump is provided with ventilation hole 33 disposed in the attachmentbody 3 allowing air to enter the bottle and replace the pumped liquid.The area of contact between the protrusions 23 and the helical grooves25 is not hermetic, so that the air can flow inside the main body 1 andinside the bottle through the ventilation hole 33. The attachment body 3is provided with an annular partition 35 surrounding the ventilationhole 33, and the main body 1 has a second annular lip 37 which sealsagainst the annular partition 35 when the pump is in its closedposition. In this way there is prevented possible leaks of the liquidfrom the bottle through the ventilation hole 33.

The head 5 is made from a material having elastomeric properties. Itcomprises a connecting portion 39 with the main body 1. This connexionmay be by any conventional means, such as welding, adhesive bonding,etc. The head 5 is also provided with a partition 41 that is the movingmember of a discharge valve 43. This discharge valve 43 is provided witha valve seat 45 disposed in the main body 1. The partition 41 may bebent resiliently such that it performs an approximate rotary movementaround the connecting portion between the partition 41 and the rest ofthe head 5 between a first position, in which the discharge valve 43 isclosed, in which the partition 41 contacts the valve seat 45, and asecond position, in which the discharge valve 43 is open, in which thepartition 41 has flexed arcuately owing to the pressure of the liquidcontained in the pumping chamber 17 On FIGS. 6 through 8 this would be aflexing to the left).

As may be seen, the partition 41 shown in FIGS. 6 through 8 is acylindrical surface extending over an angle of approximately 30°.Nevertheless, this geometry may be different, as for example thepartition 41 may be flat, undulating, or any other geometry. Likewise,its perimeter may be substantially rectangular, but is may adopt othergeometries, such as for example, oval. FIG. 16 shows another embodimentof a pump according to the invention. In this case the partition 41 is acylinder (i.e. a cylindrical surface which extends over 360°) thatcompletely surrounds the second surface 13. The partition 41 contacts asecond partition 47 disposed on the main body 1 and defining the valveseat 45 of the discharge valve 43. The second partition 47 surrounds thefirst surface 11. In this way the liquid flows out of the pumpingchamber 17 in all directions since the discharge valve 43 is annular. Atthe exit of the discharge valve 43 there is a discharge channel 49,which is also annular, and which leads the pumped liquid to thedischarge orifice. It may also be seen that in the pump of FIG. 16,there is no attachment body as an independent part, but that the mainbody 1 simultaneously forms the first surface 11, the first attachmentmeans (consisting again of a threaded portion 21), the second attachmentmeans (formed again by a projection adapted to house therein the diptube 19) and the seat of the inlet valve 9.

In the examples illustrated in the Figures, the second surface 13 is aspherical cap. Nevertheless, it could also be a flat disc-shaped surfaceclosing the pumping chamber 17. Likewise, the first surface 11 has aportion concavely curved towards the interior of the pumping chamber 17,which is substantially spherical in shape, although here again it couldbe flat or have any other geometry. The only basic requirement is that apumping chamber 17 be defined between the first surface 11 and thesecond surface 13 when the second surface 13 is in the extendedposition. Nevertheless, as stated above, the spherical geometries areadvantageous. Additionally, the main body 1 has an external rim 51convex towards the interior of the pumping chamber 17 and surroundingthe curved portion of the first surface 11.

The valve seat 45 of the discharge valve 43 has a rounded surface 53 forcontacting the partition 41 (which is the moving member of the dischargevalve 43). Further, the partition 41 is provided with a portion 55 forcontacting the valve seat 45 of the discharge valve 43, concretely withthe contact surface 53, the thickness of which tapers down towards itsfree end. As stated above, these two geometric solutions each improvethe sealing of the discharge valve 43.

The pump has two columns 57 projecting from the first surface 11 andextending to practically touching the second surface 13 when the latteris in its extended position. Both columns 57 are disposed at a portionproximate the discharge valve 43. As may be seen in FIG. 15, thesecolumns 57 prevent the head 5 from deforming in the portion proximatethe partition 41, namely, in the portion proximate the discharge valve43. In fact, what the columns 57 do is delimit more clearly which is theexternal actuation surface 15 and the second surface 13 from what is thedischarge valve 43. Thus, when the external actuation surface 15 hasbeen deformed, as shown in FIG. 15, this deformation is prevented fromextending to the portion of the partition 41, which could causeincorrect operation of the discharge valve 43.

FIG. 15 also shows how the curved portion of the first surface 11 andthe second surface 13 extend almost mutually parallel to each other.With an appropriate design, it is possible to achieve that these twosurfaces make contact, whereby it is possible to minimize the residualvolume of the pumping chamber 17.

As may be seen in the pump example shown in FIG. 15, the secondcylindrical projection 29 of the second surface 13 practically makescontact with the upper end of the tubular stem 27, when the pump is inthe open position and the second surface 13 is in the deformed position.One preferred embodiment of the invention is obtained when the relativedisplacement effected by the upper end of the tubular stem 27 whenmoving between the closed position and the open position is greater thanthe relative movement effected by the second cylindrical projection 29on moving the second surface 13 between the extended position and thedeformed position. In this way, when the pump is in the open position,the second cylindrical projection 29 is prevented from contacting theupper end of the tubular stem 27, thereby reducing the risk of thesecond cylindrical projection 29 becoming jammed in the upper end of thetubular stem 27 during a pumping movement.

In the embodiments shown, the partition 41 is always close to the end ofthe external actuation surface 15 (which is a spherical cap).Nevertheless, it is not necessary for this to be so, but, for example,the part of the head 5 and of the main body 1 corresponding to thedischarge valve 43 could extend towards the discharge tube such that thepartition 41 is further separated from the pumping chamber 17 (forexample, half way between the position it occupies in FIG. 1 and thedischarge orifice). This would allow the effect of the deformation ofthe external actuation surface 15 on the partition 41 to be reducedalso.

1. A metering pump comprising: (a) a main body having a first surface, (b) first means for attachment to a bottle neck, (c) second means for attachment of a dip tube, (d) an inlet valve, (e) a head, where said head has a second surface facing said first surface, and where said first surface and said second surface define a pumping chamber, where said head is made from a material having elastomeric properties adapted to be resiliently deformed by a manually applied force and has an external actuation surface adapted to be deformed by a user's finger, and (f) a discharge valve at the outlet of said pumping chamber, where said discharge valve includes a valve seat and a moving member adapted to move between a first position, corresponding to said closed discharge valve and in which said moving member contacts said valve seat, and a second position, corresponding to said open discharge valve, where said moving member extends from said head forming a partition, where said moving member is integral with said head, and where said first surface and said second surface are adapted to perform a relative movement therebetween causing the pumping of a liquid between said inlet valve and said discharge valve, wherein when said moving member is in said first position, and there is a reduced pressure in said pumping chamber, said reduced pressure then exerts a force pressing said moving member against said valve seat.
 2. The pump of claim 1, wherein said partition is a flat surface.
 3. The pump of claim 1, wherein said partition is a cylindrical surface.
 4. The pump of claim 1, wherein said partition is a cylinder surrounding said second surface.
 5. The pump of claim 4, wherein said valve seat is formed by a second also cylindrical partition disposed in said main body, where said second partition surrounds said first surface.
 6. The pump of claim 1, wherein said second surface is convexely curved towards an outside of said pumping chambers, and is a spherical cap.
 7. The pump of claim 1, wherein said first surface has a concavely curved portion towards an interior of said pumping chamber, and is a spherical portion.
 8. The pump of claim 7, wherein said curved portion and said second surfaced make contact in a limit of the stroke followed by said second surface during a pumping movement.
 9. The pump of claim 8, wherein said curved portion has an external rim that is convex towards the interior of said pumping chamber.
 10. The pump of claim 1, wherein said valve seat has a rounded contact surface with said moving member.
 11. The pump of claim 1, wherein said moving member has a contact portion with said valve seat having a thickness tapering down towards a free end thereof.
 12. The pump of claim 1, having at least one column on said first surface extending towards said second surface and which is disposed at a portion proximate said discharge valve.
 13. The pump of claim 12, wherein said at least one column has a height such as to contact said second surface when said second surface is in an extended position thereof.
 14. The pump claim 1 further comprising: an attachment body including said first attachment means, where said attachment body is attached to said main body for relative displacement between an open position and a closed position, and wherein said attachment body includes a projection which, when said attachment body and said main body are in the closed position, prevents said second surface from performing said relative movement.
 15. The pump of claim 14, wherein said projection is a tubular stem surrounding said inlet valve.
 16. The pump of claim 14, wherein said projection is hermetically sealed against said second surface when said attachment body and said main body are in said closed position.
 17. The pump of claim 14, wherein said relative displacement is greater than said relative movement.
 18. The pump of claim 15, wherein said main body includes a first annular lip forming a hermetic seal with the outer wall of said tubular stem.
 19. The pump of claim 18, wherein said main body includes a second annular lip forming a hermetic seal with an annular partition disposed in said attachment body, said annular partition surrounding a ventilation hole. 